It was first broken in 11.04 and has been broken since. It has been reported since 2011 and no progress has been made on the bug report.

This printer is also considered to be "End of Support" by the HPLIP project, and it is likely no resources will ever be committed to fix the real bug:http://hplipopensource.com/hplip-web/models/officejet/officejet_pro_k550.html
"The HP product has reached the end of support life, meaning the HPLIP solution is considered “As-is”. No further HPLIP code changes will be implemented by HP. While monitoring of Launchpad posts by HP personnel will continue, follow-up by HP personnel on these products will be extremely limited. Community members are encouraged to assist others with issues on these printers."

The very simple workaround is to pick hpijs instead of hpcups. This should be done by default, as it is very hard to find this bug report googling around (I thought I had a broken printer, and only after several hours spent debugging, wasting ink and paper did I find the bug report). It doesn't help that this is not a linux-only issue, as there are many people on windows having this issue so googling gets filled with bogus windows info.

Thank you.

[Impact]
Users of the HP Officejet Pro K550 are not able to print with the automatic printer setup in Ubuntu.

[Test Case]
Plug an HP Officejet Pro K550 to the USB and wait for a print queue getting auto-generated. If you have an HP Officejet Pro K550 on the network, open system-config-printer, click on "new Printer", and select the HP Officejet Pro K550 under the printers discovered in the network. Follow the steps of the wizard to complete the setup.

With the current version of HPLIP you will get a non-working queue with the hpcups driver, due to a bug in the driver which HP does not fix any more as the printer is too old.

To get it working with the proposed fix, after installing it, remove your queue(s) for the HP Officejet Pro K550 and create a new queue for it. Now the queue will use the hpijs driver which makes this printer correctly working.

[Regression Potential]
Very low, as there is nothing more done than removing the hpcups support for the HP Officejet Pro K550. All other printers should work exactly as before.

* debian/rules: Remove hpcups support for the HP Officejet Pro K550 as it is
known to not work. This way hpijs (which works) will be used (LP: #981473,
LP: #1311697).
-- Till Kamppeter <email address hidden> Tue, 29 Apr 2014 12:06:00 +0200

Uploaded a proposed fix to trusty-proposed. As soon as this package gets approved instructions will be posted here how to install it. Please install it and test whether it fixes the problem. Your feadback is required for the fixed package to get an official update.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Uploaded the fixed version 3.14.3-0ubuntu3.2 of HPLIP to trusty-proposed. As soon as this package gets approved instructions will be posted here how to install it. Please install it and test whether it fixes the problem. Your feadback is required for the fixed package to get an official update.

Please only test this package (-0ubuntu3.2), not the former one (-0ubuntu3.1)!

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

The verification of the Stable Release Update for hplip has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.